The present study outlines the synthesis of cadmium sulfide-metal-organic framework (CdS-MOF) MIL-101 (Fe) heterojunctions achieved via fast microwave-assisted reactions. Thus, different CdS-MOF MIL-101 (Fe) ratios were prepared to study their effectiveness as photocatalysts. These compounds were employed in the photocatalytic degradation of methylene blue (MB) under UV and visible irradiation. Structural, morphological, textural, compositional, and optical properties of the synthesized compounds determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were utilized to characterize the structural, morphological, textural, compositional, and optical properties. Electrochemical impedance spectroscopy (EIS) was also employed to determine photovoltage and photocurrent densities. The resulting valence band offset (V_fb) and band gap energy values were utilized to construct an energy band scheme. Our research revealed that the CdS-MOF MIL-101 (Fe) heterojunction enhances the efficiency of electron-hole pair separation, thereby mitigating charge carrier recombination effects. Moreover, the type I electronic band structure established an efficient reaction mechanism, effectively suppressing the recombination of photogenerated electron-hole pairs. The photocatalytic system demonstrated exceptional behavior, achieving complete MB removal within 30 min of reaction time and exhibiting outstanding stability and reusability after four reaction cycles. These findings highlight the potential of the synthesized compounds in the field of wastewater treatment for organic pollutants, offering a promising alternative to current environmental issues.

In this study, we tested the efficiency of nitrogen-doped titanium dioxide (N-TiO₂) and nitrogen-doped bismuth molybdate (N-Bi₂MoO₆) compounds as photocatalysts capable of degrading methylene blue and lignin molecules under irradiation with ultraviolet (UV) and visible light (VIS). Moreover, we compared TiO₂ and Bi₂MoO₆ catalysts with N-TiO₂ and N-Bi₂MoO₆ compounds using chemical coprecipitation. The catalysts were prepared starting from Ti(OCH₂CH₂CH₃)₄, Bi(NO₃)₃·5H₂O, and (NH₄)₆Mo₇O₂₄ reagents. N-doping was achieved in a continuous reflux system, using ethylene diamine as a nitrogen source. The resulting materials were characterized using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Additionally, we observed the decrease in particle size after processing the compounds in the reflux system. The results regarding photocatalytic degradation tests show a remarkable effect for nitrogen doped samples, achieving 90% of lignin degradation.

The present paper describes the results of the study of solid solutions of Bi₂Mo_xW_(1−x)O₆, which were prepared by the route of solid-state reaction and tested for catalytic activity in the oxidation of CO into CO₂. X-Ray photoelectron spectroscopy (XPS) was conducted to obtain information on the chemical composition, and with the use of Bi₂MoO₆ and Bi₂WO₆ synthesized standards, quantitative measures were obtained. Catalytic studies of the samples show that they possess high activity, as a change in the temperature of activation as a function of the sintering temperature with the Mo/W ratio was detected. Bi–Mo mixed oxides have synergistic effects on the oxidation of CO, making possible the full conversion at lower temperatures than compounds that contain only single phases. The work described here demonstrates that a solid solution can be more efficient in oxidation, compared with single oxides studied separately.